@article{fdi:010035647,
  title = {{N}eogene climate change and emergence of {C}-4 grasses in the {N}amib, southwestern {A}frica, as reflected in ratite {C}-13 and {O}-18},
  author = {{S}egalen, {L}. and {R}enard, {M}. and {L}ee {T}horp, {J}.{A}. and {E}mmanuel, {L}. and {L}e {C}allonnec, {L}. and de {R}afelis, {M}. and {S}enut, {B}. and {P}ickford, {M}. and {M}{\'e}lice, {J}ean-{L}uc},
  editor = {},
  language = {{ENG}},
  abstract = {{S}table light isotopes in ratite eggshells have been shown to be reliable indicators of shifts in climate and environmental conditions in the past. {H}ere, we show that delta(18){O} and delta(13){C} values in fossil and modern ratite eggshells collected in the aeolianite deposits of the southern and central {N}amib {D}esert track regional distinctions and global climate shifts throughout the {N}eogene. 6180 values, although variable, are consistently higher in the central compared to the southern {N}amib throughout the record. delta(18){O} trends during the {M}iocene differ for the two regions, but track each other post-{M}iocene. {T}hroughout the {M}iocene, delta(13){C} values for ratite eggshells from both the central and {S}outhern {N}amib regions are indistinguishable showing that the flora remained {C}-3 throughout. {T}he overall negative (-3 parts per thousand) shift in mean values for {M}iocene biostratigraphic zones is consistent with the response of {C}-3 photosynthesis to p{CO}(2) shifts from 180 to 320ppmv as estimated from marine alkenone studies and/or evolution of the delta(13){C} of the atmospheric {CO}2. {E}vidence for {C}-4 plants occurs post-{M}iocene, with the development of the southern, winter rainfall and central/northern, summer rainfall zonation apparent today. {T}hese data provide independent corroboration that the expansion {O}f {C}-4-dominated ecosystems after similar to 7 {M}a cannot be attributed to a reduction {O}f p{CO}(2) below a 500 ppmv threshold, as earlier proposed. {P}roliferation of {C}-4 plants in the {N}amib after similar to 5 {M}a and, elsewhere, may be related rather to energy budgets and rainfall seasonality shifts resulting from large-scale atmospheric and oceanic circulation reorganisation. (c) 2005 {E}lsevier {B}.{V}. {A}ll rights reserved.},
  keywords = {{M}iocene ; ratite eggshells ; {N}amib {D}esert ; stable isotopes ; p{CO}2 ; {C} 4 expansion ; {NAMIBIE}},
  booktitle = {},
  journal = {{E}arth and {P}lanetary {S}cience {L}etters},
  volume = {244},
  numero = {3-4},
  pages = {725--734},
  ISSN = {0012-821{X}},
  year = {2006},
  DOI = {10.1016/j.epsl.2005.12.012},
  URL = {https://www.documentation.ird.fr/hor/fdi:010035647},
}